Help: How to solve the problem of too long communication distance for instruments?
Thread Content
During the technical upgrade, flow meters and control valves were added for medium-pressure steam. However, the latest control room is located about 1,800 meters away from the site; the design institute states that signal attenuation occurs when the distance exceeds 1,000 meters, and remote communication is not recommended in such cases. I asked a professional, and they said that thickening the communication cable could solve the problem; I’m not sure if that will work Are there any other solutions?
485? A relay can be added. But I suspect you mean 4-20mA directly; a thicker wire should be fine.
For digital communication, simply thickening the wires has no theoretical effect, but in practice it does extend the communication distance； Signal attenuation in digital communication occurs because the distributed capacitance and distributed inductance of the wires cause signal distortion; when the signal becomes unrecognizable, communication is no longer possible. Therefore, simply making the wires thicker is ineffective ； Digital communication lines with relatively small distributed capacitance and inductance tend to be thicker. The claim that thick wires can increase the distance might be related to this ； Both flow meters and control valves can use direct current signal communication. For 4-20mA signals, with thick wires and proper installation, there should be no issues over a distance of 2000 meters.
Which area does the site for the technical upgrade fall into? Is it possible to add a remote control cabinet, using fiber optics to connect it to the cabinet room? 1800 meters is indeed too far; in practice, signal degradation occurs once the distance exceeds 1200 meters.
Communication with relaying, current with an active gate – that’s possible. Additionally, it might be useful to consult regarding power carriers; I haven’t used them before
If control is necessary, set up an Ethernet control station at the remote end and use fiber optics for the connection in between. Now the cost of optical fibers and converters is not high either.
It can be transmitted wirelessly; a software app can be used to view it on a smartphone, which also saves on wires
Since there is already a considerable distance, it’s better to add a control station on-site. It solves the signal transmission problem, improves the reliability of control, and the cost is not necessarily high.
For 4~20mA hard-wired signals, a 1.5mm² cable is sufficient. It’s just a flow meter and a control valve – what communication is needed? ! If this flow meter requires a measurement function, then a separate wireless communication module can be added to it; domestic ones can be obtained for around a few thousand yuan. The input and output for flow regulation still use 4–20mA hardwired connections. Simple, brutal, real, and effective.
If conditions permit, a signal gate can be added in between; if that’s not possible, wireless communication can be used. Wireless communication comes in two forms: Wi-Fi and radio, and in either case it’s important to ensure that there are no strong interference sources in the vicinity